This invention concerns a two-stage flush device for a toilet tank, particularly one having a structure for flushing a larger volume of water by rotating a rotatable button and flushing a smaller volume of water by pushing inward a push rod.
At present, a known conventional two-stage flush device for a toilet tank has a single exit tube closed by a valve, a double press rod provided with a press button A and a press rod B, by which flushing of water through an exit hole closed by the valve is controlled as shown in FIG. 1. And FIG. 2 shows that a double press button with two buttons E, F is provided for manually pressing only the button E or the two buttons E, F at the same time for flushing two different volumes of water.
However, the known conventional two-stage flush device for a toilet tank can flush two different volumes of water by means of a single exit tube, but the double buttons for flushing have the same direction of movement, and can be easily and wrongly pressed to flush the larger volume of water by accident, thereby eliminating the water saving function they are designed for.
There is another known conventional two-stage flush device for a toilet tank as shown in FIG. 3, having two exit holes H, I respectively, which are closed and opened by separate valves controlled by two press buttons J, K. This kind of structure also has the same drawback seen in those shown in FIGS. 1 and 2, in addition to possible incorrect operation of the opening of the two valves.
Another known conventional two-stage flush device for a toilet tank as shown in FIG. 4 has two separate buttons L, M for correcting flushing different volumes of water, but needs two separate holes N, O for installing the two separate buttons L, M, and consequently it is impossible to be adapted in the present toilet tanks in market or in use. So it demands a new toilet tank or an old one to be transformed a little, to a resultant extra cost in installing.